CP Chapter 13/14 Notes
The Property of Gases – Kinetic Molecular Theory
Kinetic Molecular Theory of Gases
 The word kinetic refers to ___________________________.
 Kinetic energy is the _________________________ an object has because of its motion.
 Kinetic Molecular Theory makes assumptions about:
o Size
o Motion
o Energy of gas particles
Kinetic Molecular Theory
1. According to the KMT all matter consists of tiny particles that are in constant, _________________________ motion
o Move in a __________________________ line until they collide with other particles or with the walls of the container.
2. Gas particles are much _______________________ than the distances between them. Most of a gas consists of ______________ space.
o Because they are so far apart, there are no _____________________ or ____________________ forces between the gas molecules
o The motion of one particle is ________________________________ of the motion of other particles
3. No kinetic energy is ____________________ when gas particles collide with _________________________ or with the walls of the
container ( ________________ collision)
o The total amount of kinetic energy remains ______________________________.
4. All gases have the __________________________ average kinetic energy at a given temperature
o _______________________________________ is a measure of average kinetic energy of particles in a sample of matter.
o Kinetic energy and temperature are directly related
o The ___________________ the temperature, the ________________ the kinetic energy
Absolute Zero
 The greater the atomic and molecular ______________________, the greater the __________________________ is of a substance.
 If all atomic and molecular motion would ____________________, the temperature would be at __________________ zero
( ______ Kelvin or __________ oC)
 273 + _____oC = _____________Kelvin
Diffusion and Effusion
 Diffusion – describes the ___________________________ of one material through another
o Particles diffuse from an area of _____________ concentration to _______________ concentration
 Effusion – gas escapes through a tiny ______________________________.
o The heavier the molecule, the _______________________ it will effuse or diffuse
Pressure
 Pressure is the ________________________ per unit area
 Gas pressure is the force exerted by a _______________ per unit surface area of an object.
o Gas pressure is the result of billions of collisions of billions of gas molecules with an object
 Atmospheric pressure ( ________ pressure) results from the collisions of _____________ molecules with objects.
o The air pressure at __________________ altitudes is slightly lower than at sea level because the density of the Earth’s
atmosphere decreases as elevation increases.
 Vacuum - Empty space with ____________ particles and no pressure
Measuring Pressure
 Barometer – an instrument used to measure ____________________________ pressure
 Manometer – an instrument used to measure gas pressure in a ______________________ container
Units of Pressure and STP
 Average atmospheric pressure is 1 atm
 STP (Standard Temperature and Pressure)
o 1 atm and 0oC or 1 atm and 273 K
Conversion Factors for Pressure
Example 1: Convert 2.5 atm into torr, mmHg and kPa.
1
Example 2: Convert 215 kPa into atm, mmHg, and torr.
Dalton’s Law of Partial Pressures
 Dalton’s law of partial pressures states that the _________________ pressure of a mixture of gases is equal to the _________ of the
pressures of all the gases in the mixture.
Example 1: A mixture of O2, CO2, and N2 has a total pressure of 0.97 atm. What is the partial pressure of O2, if the partial pressure of CO2 is 0.70
atm, and the partial pressure of N2 is 0.12 atm?
Example 2: There is a mixture of CO2, O2, and CO in a container. What is the total pressure if the pressure in atm if O2 is 0.563 atm, CO2 is 235
kPa, and CO is 455 torr?
The Gas Laws
_______________________ proportional - as one variable goes _______ the other goes ________ as well. Both variables do the same thing.
_______________________ proportional - as one variable goes _______ the other goes ________. The two variables do the opposite thing.
Boyle’s Law
Pressure (P) and volume (V) are
______________________ proportional.
Temperature is ____________________
T
V
P
2
Example 1: A helium balloon was compressed from 4.0L to 2.5 L at a constant temperature. If the pressure of the gas in the 4.0L balloon is 210 kPa,
what will the pressure be at 2.5L?
A sample of neon gas occupies 0.200L at 0.860 atm. What will be its volume at 29.2 kPa pressure?
Charles’s Law
Volume (V) and temperature (T) are
______________________ proportional.
V
Pressure is ______________________
Temperature must be in Kelvin.
T
o
o
Example 1: A gas sample at 40.0 C occupies a volume of 2.32 L. If the temperature is raised to 75.0 C, what will the volume be, assuming the
pressure remains constant?
Example 2: A gas sample at 55.0oC occupies a volume of 3.50 L. At what new temperature in Celsius will the volume increase to 8.00L?
3
Gay-Lussac’s Law
Pressure (P) and temperature (T) are
______________________ proportional.
P
Volume is ______________________
T
o
o
Example 1: The pressure of a gas in a tank is 3.20 atm at 22.0 C. If the temperature rises to 60.0 C, what will be the gas pressure in the tank?
Example 2: A rigid container has a gas at constant volume at 665 torr pressure when the temperature is 22.0oC. What will the pressure be if the
temperature is raised to 44.6oC
The Combined Gas Law
Example 1: A gas at 110 kPa and 30.0oC fill a flexible container with an initial volume of 2.00L. If the temperature is raised to 80.0oC and the
pressure increased to 440kPa, what is the new volume?
Example 2: An unopened, bottle of soda contains 46.0 mL of gas confined at a pressure of 1.30 atm at a temperature of 5.00oC. If the bottle is
dropped into a lake and sinks to a depth at which the pressure and temperature changes to 1.52 atm and 2.90oC, what will be the volume of gas in
the bottle?
4
Avogadro’s Principle
Avogadro’s principle states that ______________ volumes of gases at the same temperature and __________________ contain ______________
number of particles.
The _____________________ volume for a gas is the ___________________ that one mole occupies at 0 oC and 1 atm or _______________. This
is equal to _______________.
STP (Standard Temperature and Pressure) =
1 mole of gas at STP =
Example 1: Calculate the volume that 0.881 mol of gas at standard temperature and pressure (STP) will occupy.
Example 2: How many moles of oxygen gas will be contained in 5.00L flask at STP?
Example 3: Calculate the volume that 200.0 g of methane gas will occupy at STP.
Example 4: How many grams of carbon dioxide gas are in a 0.75 L balloon at STP?
The Ideal Gas Law
Ideal Gas vs. Real Gas
Ideal Gas

Real Gas

Follows ____________ gas laws under all conditions of
temperature and pressure.


Follows ____________ gas laws under some conditions of
temperature and pressure.

Follows ____________ conditions of the Kinetic Molecular
Does ______________ conform to the Kinetic Molecular
Theory (KMT)
Theory. Real gases have a ____________________ and
An ideal gas does ________________ exist in real life
attractive and __________________________ forces.

A real gas differs from an ideal gas the most at
_____________ temperature and ____________ pressure.
5
Ideal Gas Law
Ideal Gas Law – Using Moles
Example 1: Calculate the number of moles of gas contained in a 3.00L vessel at 298K with a pressure of 1.50 atm.
Example 2 What pressure will be in kPa when there are 0.400 mol of gas in a 5.00L container at 17.0oC.
Gas Stoichiometry
When gases are involved, the coefficients in a balanced chemical equation represent not only molar amounts (mole ratios) but also relative volumes
(volume ratios).
C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(g)
Example 1: What volume of oxygen gas is needed for the complete combustion of 4.00L of propane gas (C3H8)? Assume constant pressure and
temperature.
Example 2: How many liters of C3H8 is needed to produce 8.00L of CO2?
Example 3: What volume of oxygen is needed to completely combust 5.67 L of methane gas (CH4)? Write and balance the equation.
6